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Different aluminum and calcium based particles, montmorillonite (MMT), zeolites (NaY), bayerite (BAY) and hydroxyapatite (CaHAp), were compared and evaluated for water defluorination. The effect of parameters such as temperature of the medium, concentration (mass of adsorbent), reaction time and pH on the defluorination capacity were studied for the particles with best performance. MMT and CaHAp adsorbents showed increased fluoride rejections in batch experiments (approximate to 45 and 100%). The defluorination capacity of MMT is influenced by the concentration and pH, while for CaHAp is independent of the evaluated parameters within the measured range. Further, polymer composite membranes based on poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) and the adsorbents with higher defluorination capacity were prepared by thermally induced phase separation in order to produce active filters for fluoride removal from water. The composite membranes presented a homogeneous porous structure with degrees of porosity ranging between approximate to 20 and 76% and average pore size in the micron range. The permeability of the composite membranes ranged between 12,500 and 10,000 L/h.m(2).bar. A maximum fluoride rejection of 68% was obtained after 6 filtrations for the CaHAp/P(VDF-HFP) composite membranes. Thus, the composite membranes of P(VDF-HFP) with MMT and CaHAp show suitable performance for defluorination in water purification systems., This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013. The funds provided by FCT through the Chemistry Research Centre of the University of Minho (UID/QUI/00686/2013 and UID/QUI/0686/2016) are also gratefully acknowledged. JNP wish to thank the financial support of the project Centro-01-0145-FEDER-000017 - EMaDeS - Energy, Materials and Sustainable Development, co-financed by the Portugal 2020 Program (PT 2020), within the Regional Operational Program of the Center (CENTRO 2020) and the European Union through the European Regional Development Fund (ERDF). The authors acknowledge funding by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (AEI/FEDER, UE) (including the FEDER financial support), and financial support from the Basque Government Industry Department under the ELKARTEK and HAZITEK program. PRS gratefully acknowledge DST Women Scientists Scheme-A (WOS-A) for the research grant SR/WOS-A/CS-91/2013., info:eu-repo/semantics/publishedVersion

A series of dysprosium (Dy) doped LiMn2O4 based spinel cathode materials, LiMn2 − xDyxO4 (x = 0, 0.01, 0.02, 0.03, 0.04, 0.05) for Li ion rechargeable battery application were synthesized by sol-gel process. The physical properties were explored through X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray diffraction (EDX), field emission scanning electron microscopy (FE-SEM), and micro-Raman spectroscopy. Swagelok cell configurations were used for electrochemical characterizations e.g. cyclic voltammetry, rate performance, cycleability and AC impedance. The doping amount of dysprosium has improved the surface morphology (particle size

Download : Download high-res image (81KB) Download : Download full-size image The current study involves a simple hydrazine based colorimetric chemo-sensor for selective determination of various anions. The anion-binding ability of the ligand with various anions via polar-non polar interactions and hydrogen bonding has been examined. The sensor displayed significant UV–vis enhancement response to anions such as fluoride, acetate, hydroxide, cyanide and hydrogen sulphate, with respect to concentration and time. The rate constants (K) and binding constants, Ka, for these anions have been measured by using Benesi-Hildebrand equation. A time dependent NMR study revealed stronger interaction for cyanide and fluoride ions among competing anions.

The Ni/Co-natural clay catalysts have been prepared for the conversion of algae oil into diesel-grade hydrocarbons. Methyl oleate was used as a model compound for the present study. Ni/clay catalyst promotes decarboxylation/decarbonylation, whereas remarkable selectivity in hydrodeoxygenation (HDO) is achieved with Co/clay catalysts. Powder XRD and DRS studies of substrate mixed catalysts reveal a more prominent adsorption of substrate molecules over the Ni surface, which results in low HDO selectivity of nickel catalysts by surpassing the essential contribution of acidic sites. The HDO process provides higher carbon atom economy and energy value over decarboxylation/decarbonylation, while further reducing the formation of greenhouse gases such as CO2 and CH4. Total yield of saturated hydrocarbons from algae oil was 84–86 wt % with similar selectivity. The HDO rates of different fatty acids present in algae oil were independent of the fatty acid chain length. The catalysts are cost-effective and recyclabl...

LiMn1.5Ni0.5O4 with spinel type of structure was synthesized by sol-gel method and doped by different rare-earth elements (Nd, Gd and Dy). It was found that the inclusion of rare-earth element preserves the cubic spinel structure, leads to smaller particle size and improves the cyclic performance of the produced batteries. The best battery performance was obtained after doping the spinel structure by Gd. Among the used rare-earth elements Gd is the only one with stable oxidation state of 3 + which leads to stabilization of the Mn dissolution.Thus, the improvements observed in battery performance (rate performance and cycle life) are due to the superior structural stability of the doped active materials. It is concluded that the LiMn1.48Ni0.5Gd0.02O4 sample is the one with the best overall performance to act as active material for cathodes in rechargeable lithium-ion batteries., This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013. The authors thank FEDER funds through the COMPETE 2020 Programme and National Funds through FCT under the projects PTDC/CTM-ENE/5387/2014 and UID/CTM/50025/2013 and grants SFRH/BD/90313/2012 (A.G.), SFRH/BD/88397/2012 (R.G.) and SFRH/BPD/112547/2015 (C.M.C.). The authors are thankful for funding from the FCT under the Indo-Portuguese program of cooperation in science and technology (INT/Portugal/P-02/2013) 2014-2016. The fellowship from MHRD, Govt. of India was acknowledged for Pura Ram. Financial support from the Basque Government Industry Department under the ELKARTEK Program is also acknowledged. The authors acknowledge the MRC, MNIT, Jaipur, Rajasthan, India for TEM, RAMAN characterization facilities for material characterization., info:eu-repo/semantics/publishedVersion

LiMn2-xGdxO4 (x=0.00, 0.01 and x=0.04) spinel active material were prepared by sol-gel method. The morphology, crystal structure, thermal stability and electrochemical properties of the synthesized samples were evaluated. Gd-doping maintains the cubic spinel structure of LiMn2O4, leads to a decrease of the average particle size, and has a strong influence on the electrochemical properties of the cathodes. LiMn2-xGdxO4 cathode materials show two pairs of separated redox peaks, independently of the Gd-doping. After 40 charge-discharge cycles at C2, the discharge capacity was 55.9 mAh.g-1 and 33 mAh.g-1 for x=0.04 and x=0, respectively, corresponding to a capacity retention of 80% and 70%, respectively. The Gd-doped with x=0.04 showed improved cycling performance with respect to pristine LiMn2O4 due the smaller particle size and superior structural stability, showing its suitability for lithium-ion battery applications., The authors thank FEDER funds through the COMPETE 2020 Programme and National Funds through FCT - Portuguese Foundation for Science and Technology under Strategic Funding UID/FIS/04650/2013. A. G., C.M.C. and S. F. thank the FCT for grants SFRH/BD/90313/2012, SFRH/BPD/112547/2015 and IF/01516/2013, respectively. The authors thank funding from the FCT under the Indo-Portuguese program of cooperation in science and technology grant INT/Portugal/P-02/2013, 2014-2016. The authors are thankful for HRTEM and Raman characterization support from MRC, MNIT, Jairpur, INDIA. The fellowship from MHRD, Govt. of India was acknowledged for Pura Ram. SLM thanks financial support from the Basque Government Industry Department under the ELKARTEK Program.

The present study describes non-covalent interaction and complexation behaviour of sodium ascorbate (SA) with cucurbit[6]uril (CB[6]) at neutral pH in aqueous Na2SO4 solution. The interaction behaviour is investigated using various analytical techniques like NMR, UV–Vis, fluorescence, TGA and DRS. The substantial increase in the intensity of emission and absorption spectra of sodium ascorbate is observed. The Benesi–Hildebrand evaluation method is used to determine the stoichiometry and equilibrium constant of the cucurbit[6]uril–sodium ascorbate complex, which suggested the 1:1 complex. Time-dependent 1H NMR, 13C CP MAS and CD studies also echoed non-covalent interaction between SA with CB[6].